Analog Devices Inc. AD7864BSZ-1

Overview

AD7864BSZ-1 from Analog Devices is a 4-channel, simultaneous-sampling, 12-bit analog-to-digital converter (ADC) with 1.65 μs conversion time, ±10 V/±5 V input ranges, on-chip 2.5 V reference, and high-speed parallel interface. It preserves phase coherence across channels and targets real-time motor control and power monitoring systems requiring synchronized multi-channel acquisition.

For engineers reviewing the AD7864BSZ-1 datasheet, AD7864BSZ-1 pinout, AD7864BSZ-1 application, or AD7864BSZ-1 equivalent, key selection considerations include simultaneous sampling capability, aperture delay matching ≤4 ns, bipolar input support, 130 kSPS four-channel throughput, and MQFP-44 package compatibility with industrial signal conditioning designs.

Technical Context

The AD7864BSZ-1 integrates four independent track-and-hold amplifiers with matched aperture delay (≤4 ns), enabling true simultaneous sampling of four analog inputs while preserving inter-channel phase relationships. Its internal 2.5 V reference (±20 mV error over temperature) and programmable channel sequencing via SL1–SL4 pins or software register allow flexible configuration without external timing components.

Conversion is initiated by a single CONVST rising edge that places all T/Hs into hold mode and latches channel selection. BUSY remains high until all selected channels complete conversion; EOC pulses low after each individual channel's result is ready. The device supports both internal clock (1.65 μs conversion) and external clock modes (e.g., 5 MHz), with read-during-conversion operation achieving up to 130 kSPS aggregate throughput.

Key Specifications

Pinout & Package

AD7864BSZ-1 is housed in a 44-lead MQFP (Metric Quad Flat Package) with 0.8 mm lead pitch and 10 mm × 10 mm body size. Pin 1 is marked by a dot; leads are numbered counterclockwise from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-channel simultaneous-sampling ADC applications.

Compared with AD7864BSZ-1, AD7656ASTZ trades speed and interface flexibility for resolution, while ADS8556IPM adds channels and resolution at the cost of power and package size - AD7864BSZ-1 remains optimal for cost-sensitive, space-constrained 4-channel 12-bit simultaneous sampling where parallel bus integration is preferred.

Availability

AD7864BSZ-1 is available at Aetrix Electronics and suitable for AC motor control, uninterruptible power supplies, and industrial data acquisition systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AD7864BSZ-1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7864 product line was designed specifically for industrial real-time systems demanding synchronized multi-channel acquisition - emphasizing aperture matching, robust input protection, and direct microprocessor interfacing without external support circuitry.

FAQ

What input voltage ranges does the AD7864BSZ-1 support?

The AD7864BSZ-1 supports ±10 V and ±5 V bipolar input ranges, as specified in its ordering designation "-1". These ranges are factory-configured and cannot be changed in-circuit. Input overvoltage protection allows transient excursions to ±20 V (for ±10 V range) without damage, making AD7864BSZ-1 suitable for noisy industrial environments where sensor faults or switching transients may occur.

How does the AD7864BSZ-1 achieve simultaneous sampling across four channels?

The AD7864BSZ-1 achieves true simultaneous sampling using four independent track-and-hold amplifiers, each associated with one analog input pair (VIN1A/B through VIN4A/B). A single CONVST rising edge freezes all four T/Hs at the exact same instant, capturing phase-coherent snapshots. This architecture - confirmed in the Functional Block Diagram and General Description - ensures aperture delay matching ≤4 ns, which is essential for vector-based control algorithms relying on precise inter-channel timing.

Can the AD7864BSZ-1 interface directly with a 3 V microcontroller?

Yes, the AD7864BSZ-1 supports direct interfacing with 3 V processors via its dedicated VDRIVE pin (Pin 36), which powers the DB0–DB11 data bus, BUSY, EOC, and FRSTDATA outputs. When VDRIVE is supplied with 3 V ±10%, the digital outputs meet 3 V logic thresholds (VOH ≥ 2.4 V, VOL ≤ 0.4 V), eliminating the need for external level shifters. This capability is explicitly documented in the Logic Outputs section of the datasheet and verified in timing characteristics for VDRIVE = 3 V.

What is the purpose of the FRSTDATA pin on the AD7864BSZ-1?

The FRSTDATA pin (Pin 2) is a logic output indicating when the internal output data register pointer addresses Register 1 - i.e., the first valid conversion result after a sequence begins. It goes high at the start of the read cycle and remains high until the next CONVST triggers a new sequence. This signal simplifies FIFO or DMA handshaking in systems where multiple conversions are buffered, allowing the host processor to identify the beginning of fresh data without polling or fixed delays - a feature confirmed in the Pin Function Descriptions table.

Does the AD7864BSZ-1 include an internal voltage reference?

Yes, the AD7864BSZ-1 integrates a 2.5 V bandgap reference with ±20 mV maximum error over temperature (−40°C to +85°C) and 25 ppm/°C typical temperature coefficient. This reference is accessible at the VREF pin (Pin 24) and serves both as the ADC's conversion基准 and as an output for external circuitry. The datasheet confirms its use in the General Description, Specifications table, and Reference section - and allows overdriving with an external 2.5 V source if higher stability is required.